The tasks of the Clinical Core are to a) provide treatment plans, quality assurance and monitoring of treatment delivery for patients treated in the Research Projects (RP), b)gather setup uncertainty data for head and neck patients, c) implement specialized treatment methods to enhance tumor localization and reduce the effects of treatment uncertainty developed in the research projects, and d) work with the Computer/Dosimetry Core and RPs to implement improvements to the treatment planning software. Intensity modulated radiotherapy (IMRT) plans will be designed for the treatment of prostate, nasopharynx and non-small cell lung tumors. For prostate tumors, plans will be created for patients treated with either 86.4 Gy IMRT or 75.6 Gy IMRT plus adjuvant androgen deprivation. The feasibility of image-guided "dose-painting" using IMRT in prostate cancer will also be evaluated using the image registration and delivered dose calculation methods developed in RP 3. This study will establish the limitations of IMRT to deliver 91.8 Gy to suspected tumor-bearing regions within the prostate. Patients with non-small cell lung tumors will be entered into a dose escalation study and will receive radiation alone or concurrent radiation and chemotherapy. They will be planned and treated with respiratory gated IMRT. Tumor localization will be improved with the use of respiration-gated PET/CT images. Plans will be designed using CT images from the portion of the respiratory cycle showing minimum tumor motion, selected from spiral CT images correlated with respiration. Fifty patients will be treated using megavoltage cone-beam CT imaging (MVCBI) to visualize tumor position during treatment. The IMRT plans for these patients will be designed with explicit consideration of the dose delivered during MVCBI. Patients with nasopharynx cancer will be entered into a Phase I dose escalation study, receiving either 70.2 or 75 Gy using osepainting and IMRT. Plans will deliver a non-uniform dose distribution concurrently treating sites of gross disease to 2.34 or 2.5 Gy per fraction and electively irradiated regions to 1.8 Gy per fraction. MR and PET images will be used to improve target and normal tissue localization. Techniques will be developed using enhanced inverse planning tools designed by the Computer Core to minimize salivary gland and cochlear doses. Setup uncertainty will be measured and incorporated into dose calculations facilitating an analysis of delivered dose to the tumor and normal tissues. Improvements in the inverse planning system will include biophysical models from RP 1b, i.e. improved normal tissue complication probability calculations for rectal bleeding, tumor control probability for nasopharynx tumors, and dose response data for sensorineural hearing loss, etc., applied to plan design as they become available.